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(No Model.)

' W. D. SMITH.

AIYR HEATING APPARATUS. No. 374,094. Y Pajtented Nov. 29, 1887.

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UNITED STATES PATENT OFFICE.

WRIGHT D. SMITH, OF DETROIT, MICHIGAN, ASSIGNOR TO THE HUYETT 85 SMITHvMANUFACTURING COMPANY, OF SAME PLACE.

AIR-HEATING APPARATUS.

SPECIFICATION forming part of Letters Patent N o. 374,094, datedNovember 29, 1887. Application tiled October 2S, 1886. Serial No.217,427. `(No model.)

struction and combination of the parts with.

I5 relation to each other, as more fully hereinafter described andclaimed.

In the accompanying drawings, which form a part of this specitication,Figure l represents my invention in perspective, with parts of the wallof the air-heating chamber broken away to show the interior arrangement.Fig. 2 is a central vertical section ot' the fancase and its flaringmouth.

A represents a box, preferably made of sheet metal and rectangular inform, with an open discharge end communicating with the drykiln, whichlatter is not shown. The header-pipe B passes through the ends of thisbox, near one of its upper corners, and upon its projecting ends, onebeing at either end of the box, a suitable cut-ott' valve, C C', is"

placed, and one of the projecting ends is connected with the exhaust ofthe engine that may be employed for driving the apparatus,`

while the opposite end is connected with -the live steam ofthe boiler,so that the exhaust or live steam may be used,as desired, by opening theproper valve for its admission and closingthe opposite one. io D is asimilar header-pipe extending along one of the lower corners of such boxA, and projecting a-t both ends for the purposes of exhaust and livesteam condensation and outlet, and these projecting ends are providedWith other suitable valves. Preferably this header-pipe D is diagonallyopposite the header-pipe at the top of the box, and the two header-pipesare connected together by a series of steam coil-pipes, E, each coilbeing 5o independent from the others and connected at top and bottomwith the header-pipes B and D, care being taken that the area of boththese header-pipes is not greater than the ,area of the pipes formingthe coils in crosstion, (driven from any suitable source of 6o power,)drives the air centrifugally into the box A, through the flaring mouthG, which affords communication between the fan and the interior ofthebox A, to which latter such flaring mouth is secured around an openinglarge enough to admit of the centrifugal action of the air in beingforced into the box, so that in the passage of such air through such boxit is brought into contact with all, or nearly all, theradiatingsurfaces of the pipes of the steam- 7o coils and headers, andto this construction I attach importance.

I find by experience that with this construction I am able to heat alarger volume of air and to carry the same into the dry kiln with agreat 4saving of labor to the fan, and that the air discharged into suchdry-kiln is of a higher' temperature when thus forced through theheating-chamber than when drawn through by a suction-fan located at theopposite end 8o of the heating-chamber to that where I locate inyVentilating-fan, in which latter construction the fan agitates and coolsthe air.

For many commercial purposes hot air is needed, and this device can beregarded as a 8 5 hot-blast apparatus adapted to such purposes.

Vtfhat I claim as my invention is- The combination, in a hot-blastfurnace, of the box A, inclosing steam-coils, with a diskfan with itsaxis parallel with the length of 9o said box, and a flaringcommunication between the fan case and box, whereby the centrifugalforce of the fan will drive the air into all parts of the box,substantially as and for the purpose specified.

W, D. sMrrH.

